Sewing-machine



(No Model.) 3 Sheets-Sheet 1.

R. W.-THOMSON. SEWING MACHINE,

No. 545,391. Patented Aug. 27,1895.

Vii/b93383 J [7 1,77 77,190

(No Model.) 3 Sheets-Sheet 2.

R. W. THOMSON. SEWING MAUEINE.

No. 545,391. Patented Aug. 27, 1895.

FV/f 71 away I? M 71 1507 \g/ LA/ZLQC/AM" 1 01 W. Th (meson UNITED STATES PATENT OFFICE.

ROBERT W. THOMSON, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THE PHILADELPHIA EARRING MACHINE COMPANY, OF CAMDEN. NElV JERSEY S EWING-MACHINE.

SPECIFICATION formingpart of Letters Patent No. 5d5,3 91, dated August 27, 1895.

Application filed July 30,1894. Serial No. 519,019. (No model.)

To aZZ whom it may concern.-

Be it known that 1, ROBERT W. THOMSON, a citizen of the United States, and a resident of Lynn, Massachusetts, have invented certain Improvements in Sewing'-Machines, of which the following is a specification.

My invention relates to sewing-machines of that class in which successive groups of stitches are formed at intervals upon the fabric, an ordinary button hole-barring machine being an example ofja machine of this class; and the object of my invention is to preventthe laying of the needle-thread on the surface of the fabric from one gronpof stitches to the other to be afterward trimmed off. This object I attainby severing the needle-thread beneath the fabric after each group of stitches has been completed, so that in starting each fresh course of stitches the needle-thread will have a loose end, which will be drawn down through-the fabric to the under side of the same by the action of the shuttle, looper, or other under-thread mechanism in completing the first stitch of the new group.

In the accompanying drawings I have illustrated my invention as applied to a barring or tacking machine of the character represented by H. L. Kemps patent, No. 466,607; but it will of course be'undcrstood that the invention is not limited to amachine of this type, but is applicable generally to machines at the class above referred to.

In the accompanying drawings, Figure tie a perspective view of suflicient of the machine to illustrate my invention. Fig. 2 is a view of the under side of the machine with the under-thread mechanism removed in order to illustrate devices constituting part of my in: vention, and which would otherwise be hidden by said under-thread mechanism. Figs-3 and 4. are views illustrating the thread-severing mechanism in diifcrent positions fromthat represented in Fig. 2. Fig. 5 is a view illustrating a modification of the thread-severing device, and Fig. 6 is a view illustrating a modified form of mechanismfor operating the threadsevering device.

A represents the bed-plate; B, the needlehar D, the presser-bar; F, the movable clamping device for carrying the fabric, and G the cam-disk for operating the same, as in the V aforesaid Kemp patent, the lever mechanism,

whereby the cam acts upon the clamping device to impart the desired movements thereto, not being shown in my drawings, as it forms no part of my invention and would, if illustrated, interfere with the proper showing of parts to which my invention does relate.

Suitably guided on the under side of the machine is a slide a, carrying a knife 5, which has aprojecting finger d, preferably unsharpened and contracted in width, this finger during the operation of the machine occupying a position adjacent to the needle'opening of the work-plate, as shown in Fig. 53. The knifeslide a has a pin a, which is engaged by the slotted arm of a bell-crank leverf, hung to the under side of the machine, the other arm of said lever being-connected by a rod f to the lower end of a lever g, which projects through an opening in the bed-plate A of th'em'achine and is .hung to a suitable bracket -g'- on said bed-plate, as shown in Fig. l, a spring g serving to draw the lower end of the lever 9 rearward in order to retain the knife-mide a in the retracted position shown in Fig. 2. The upper end of the lever g projects into the path of 3. lug g on the cam-disk G, this lug being so disposed that it will act upon the lever 9 just before the completion of the last of the lever 71. is beveled, as shown in Fig. 1,

for the action of a pin 'm, which is carried by a. lever m',\hung to a bracket m on the bedplate, and having another pin m, which acts upon hooked fingers m on the upper plate of the work-holding clamp, the rear end of the lever m being connected by a rod m to suitable treadle mechanism, whereby when the formation of a group of stitches is completed the upper plate of the clamp can be raised ICC and the work read justed therein to the posiof the thread occupy theinoperative position shown in Fig", 2; but as 'the last stitch is be tng formed the action of the lug g of the cam disk G upon the lever g causes the 'latterto project the-knife-slide a to the position shown in Fig. 3that is "tosayfsomhat the contracted forward end or finger d of"the knife blade will enter the loop ofneedle thread-'- whereby, as the needlecontinuesto rise, said loop will be drawn tight around said contracted finger before the automatic stop motion before mentioned comes into play to stop the needle and feeding devices. The

same movementof the knife-slider; which thus projected the knife-blade brought the pin '21 into the path ofthe beveled cam-slide i, as shown in Fig. 3, and when the lever m is operated so as to raise the top bar of the clamp, in order to release the work, the pin mof said lever m will act upon the beveled.

upperendof the lever h, so as to cause vibration of said lever and a projection -of the cam- -slide a", the beveled front end of said slide acting upon the pint of the knife-slide a so as to efiect a still further projection of-the knife and a severing ot the loop of needlethread which has been formed-upon the same, as shown in Fig. 4; As soon as the lever m has been permitted to assume its normal position the earn-slide z" its-withdrawn and the knife-slide a permitted to return to the posi: tion shown inFig. 3, and the first movement of the machine, in starting to form a new group of stitches, carries the lug g of the camdislr G away from the upper end of the lever 9, so as to permit of the further retraction of 'theknife-slide to its normal or inoperative position, as represented in Fig. 2. When the needle-thread is cut, a 'loose end-is left hanging-from the eye of the needle as the.

latter rises, but in starting a new group of stitches the loose end of needle-thread is drawn down throughthe fabric by the action of the 'u'ndenthread mechanism, so that no needle-threadappearsnpon theface of the fabric between stitchesiormed thereon, and the usual subsequent trimming operation is thus rendered.

unnecessary,

'lnorder to prevent the-loose endof the needle-thread from being accidentally withdrawn from the eye completion of one group of stitches and before starting the next group, I find it advisable to provide the needle-bar B of the ma- 1 chine with a frictional thread-retainern independent of the usual tension device, through which retainer the thread passes after leaving the take-sperm I' of the machine and before, assing' through thev needle-eye, this three the successive groups of of the needle after the.

eye that there is very little slack in the thread between the two, and hence very little tend- -ency to withdraw the loose'end of the thread from the eye. i

prefer to adopt the construction of cutting embodying the essential features of my invention may be resorted to, For'instance, in Fig. 5 I have shown one such modification in are formed upon the work-plate of the machine, the knife-plate b in this case being replaced by a simple puaher-plate b whereby the loop of needle-thread is pushed onto the finger d and against the knife b',:and other equally obvious modifications of the cutting mechanism are permissible within the general scope of my invention. The cutting movement of the knife may also,- il' desired, be due to the swinging movement of the stop-m'otion lever instead of to the movement of the clampreleasin'g lever. Thus in Fig. 6 I have illus treated a construction in which the lower end slide p, which actsupon a pin p, intended tobe carried by the rear end or the rod 2'), whereby the stopping of the machine .will of feet the automatic projection of thercam-slide 11, so as to complete the movement of the knife-slide. It will be evident, therefore, that my in'vention'in its broadest form 'is independent of the special construction of the knife and of the mere mechanical devices for efiectingthe movement of the knife or pusher plate, whereby the severing of the needle- 'thread beneath the'fabricis effected. If the knife is too dull vto cut the thread,.t he same will be severed, as-the strain upon the loop where the wedge-shaped'portion of the blade is pushed into the same will break the thread, and a machine might, in accordance with the main feature of my invention, be constructed vice may also, if desired, sever the under this case, the-blade should be so wide that sufwhen the next group of stitches is begun.

Having thus described my invention, I claim and desire to secure by Letters Patent- 1. In a machine for forming successive groups of stitch'es with intervening spam, 'fhecombination of the stitch forming and Lwork feeding? devices, with mechanism-tor severing the thread beneath the work, said mechanism comprising a device for-entering the loop'of the the same is drawn-tight and a cutting blade the combinationof the'stitch forming -1etai'ner being so close to the-needlework leedingdevices, with cutting mechanism Although in carrying out my invention I,

which a. loop-receiving finger d and knife b' of the stop-motion lever p carries a beveled ficientslack will be formed in said" under thread to permit it to. engage with the fabric knife shown in Figs. 1 to 4, other constructions with-the view of purposely breaking instead. ofcutti-ng the needle-thread. The cuttingde' thread, as well as the needle-thread; but in last stitch of the group before I or knife forsevering the thread after the same for severing the needle thread beneath the work after the formation of eachgroup of stitches, one of the elements fiseid cut-ting mechanism being a contracted blunt finger, projecting from ablade or knife, for entering the loop of needle thread before the same is drawn tight to complete the laststitch of the group.

S. In a machine for formingsnccessive'. groups of stitches with intervening-spaces, the combinationof thestitch forming'nnd work feeding devices with mechsnism ior sew ering theneedle thread beneath the work-before the completion of the last stithbii-ftho group, said severing mechanism comprising a finger for entering the loop of needie thread b'efore'the same isdrawn tight tic-complete the East stitch, a knife-end reciprocating mechanism therefor, said mechanism-cow,

prising two independent sets of operating devices, the-first causing a primary stage of causing the the movemenhand the second final stage of the same.

at In a machine for forming successive groups of stitches with intervening spaces,

, the combination ot the stitch forming and work fecdingdevices, with mechanism for severing the needle threads beneath the Work on the completion of a group of stitches, aidevice for entering the loop of thelast stitch of the gronp before the same is drawn tight, the cam which controls'the operation of the feed ing device, and connections between seid'cam and severing mechanism, whereby the said cam causes the severing mechanism to out the thread beneath the work after the last stitch of eachgroup has been completed,snbstantially as described. I

5. In a machine for forming successive groups of stitches with-intervening spaces, the combination ofthe stitch forming and work feeding devices, with a severing device having a two-siege movement, whereby it is caused to sever the needle thread beneath the work on the completion of the last stitch of each group, the cam which controls theoperation of the feeding devices, the lever which effects the opening of the clamp of the work holder, mechanism whereby the feed controliing cam is caused to impart to the "severing device the firststage of its movemenflandmechanism whereby the clamp opeuing'leverris caused to impart to said severingdevice the fined stage of its movement, substantially as described.

6: In a machine for forming successive groups of stitches with intervening spaces, the combination of the stitch forming and work-feeding devices, with a device adapted to sever the needlethread beneath the work the combination of the stitch forming and work feeding devices, mechanism whereby work on the completion of each group of stitches, and a frictional retaining device for the needle thread independentof the neon tension device and mounted upon the needle bar, substantially as specified. g

In testimony whereof I have signed my name to this specification in the presence of two subscribing-witnesses.

ROBERT W. THOMSQN.

- Witnesses: JeooB M, Lewis,

MELVILLE P. Nioxnnson.

the needle thread is severed. beneath the 

